In order to achieve an unlimited degree of freedom of rotation between two units, it is known to provide two ball bearings axially displaced relative to each other and to tension them in axial direction against each other. This results in high translational rigidity. A low friction results about the axis of the degree of freedom of rotation.
It is known to align ball bearings in a bearing sleeve or the like at the outer surfaces of the outer bearing races. However, defects of these surfaces with respect to the raceways of the ball bearing races affect the mounting and, for example in gyro mountings, result in drifts of the gyro.
A fixed mounting for a spindle having a rolling bearing transmitting the radial forces of the spindle and a crossrolling bearing taking up the radial forces is known from DE-A-37 10 185. A spacer ring is located between the outer rings of the rolling bearings. Compression springs are built in into the spacer ring and adjust the outer race of the radial rolling bearing to eliminate backlash. A resiliently yielding spring ring is built in between an end face of the outer race and a housing cover in order to hold the outer race on a shoulder of the spacer ring without the risk of an inclination.
U.S. Pat. No. 4,665,605 shows a cardan arrangement for driving a dynamically tuned gyro. A gyro rotor is coupled to a driving shaft through this cardan arrangement.
In the journal "Plaste und Kautschuk" (1956), 127-130, the application of glues in mechanical engineering is described. For example, bearing bushings are eccentricity-free glued in place in bores of a machine element by means of a centering device.
In a company brochure No. 41 114 "FAG Spindellager fur Werkzeugmaschinen" of FAG Kugelfishcher Georg Schafer & Co, Schweinfurt, pairs of spindle bearings are described which are biased by cup springs. Thereby, running free from backlash and high rigidity of the spindle system is achieved. Both of the bearings are loaded in all of the operational states.
DE-C-30 18 091 describes a shaft bearing free from backlash for a gyro rotor having two coaxial rolling body systems, the axial bias of which is adjustable. The outer raceways of the systems are formed by an integral bushing. One of the inner raceways is formed by the shaft. The other inner raceway is formed by an inner bearing ring. The inner bearing ring is located on the shaft with a fit which permits displacement by high axial force only.
DE-U-86 31 287 shows a mounting for a shaft in which an abutment is arranged between an axial bearing and a radial bearing, this abutment being formed as insert, takes up forces and is connected to a housing. Several spring elements acting on the races are provided within the abutment. Thereby, the bearing is always biased.